TURBO FOR 2.8L?

[El-Stupido]

if the turbo only flows about 336cfm, and the motor pumps about 245, that doesnt leave room for much boost, ts just math. i could be wrong, been feeling pretty mindless lately, but if i size it acording to "maximum boost" the turbo comes out small.
177ci @ 6000rpm = 245.8cfm
t3 "60" trim = 336cfm
336/245.8=1.36pr
actually comes out to 5.29 psi that sux.
i could crank it up for mid rpm, but why limit it?

[z24turbo93]

umm okay i don't get it but whatever you think because umm let me see i run 8 psi on a 3.1 engine and can run how much i really wanna run. so i don't get where you are coming up with the turbo can only run 5.9 psi or whatever you said.

[nocutt]

...Too many variables that even go beyond the board...
Generally speaking though, the higher you go in compression, the less boost you can/need to run and the less timing...assuming we are only stuck with pump gas. Remember pump gas also differs from demographics to demographics...I am strictly speaking of octane! Also the higher the static compression the smaller the "the tuning window" becomes, however the better the offboost response( throttle ), the flatter the curve and the better the fuel efficiency...
The quench area (squish area) is what I like to call "designed octane". The theory of how it works is very interesting. The quench area are designed flat areas within the combustion chambers...typically, bottom of the heads and the pistons. They also have the capacity of the absolute combustion chamber between them. As I understand it, the pistons and heads are designed with this qualities whereby when the mixture is been compressed, the AFR is "squished" towards the center of the chamber, where it is more hotter especially due to the plugs activity. This procedure also culminates a cooling effect known as "quench". It is obviously more complicated, this was a basic overview. However the consesus still remains; to run a 9.5:1 CR on the street and you wish/want longevity, limit boost add enough timing (enough at least to not having Knock or add more octane. Technology has really made the original question...questionable

You will be very limited with placement of an IC in your fiero...

[Mechanic]

That?s a fairly good explanation of cylinder quench, although it can apply to most any head type with the proper piston design.
The basic idea is to use a dished piston, with an optimized distance of around .030 for piston/head clearance. The abilty to obtain this distance on a non-splayed valve head would be the determining factor for its application there.

When GM finally caught on to the fact that optimized cylinder quench was critical to good engine design, they were able to increase the cr of the 3.1 60V6 from 8.9 to 9.6 using the same fuel octane rating. The result of this along with many other significant improvements, was the GEN III 60V6.
The reason they were able to acheve such a drastic increase in static cr, is the increase in detonation threshold that quench optimization provides. Detonation threshold also happens to be the primary factor used in determining gasoline octane ratings.

The design of the forged pistons I use is based directly on the GEN III 3100 SFI design (i.e. same compressed height, etc), with an increased dish volume to lower the cr from 9.6:1 to around 9.0:1. Since the optimized quench distance is retained, this is actually the equivalent of an 8.3:1 cr if one were using the non-optimized 3.1 Vin T piston design.

Successful turbo charging of an application that uses iron heads with a "higher than stock" cr forged piston, would really depend on weather the piston incorporates an optimized quench design. If not then I would say that one would be much better off using a nitrous oxide system as a power adder.

In any event, the stock Fiero engine management system does not include ESC control via knock sensor. The lack of a knock sensor eventually results in "several thousand pieces of piston" when significant boost is applied, since "precise tuning" is quite hard to achieve without one.
The 85 Fiero V6 ECM included ESC control / knock sensor options, which might be an alternative if one could also obtain a 2-bar version of the $24a code.
I have yet to see what would be considered as an acceptable 2-bar conversion of this code (IMO), although some claim to have accomplished it, (i.e buyer beware).

Other forced induction Fiero V6 engine managment alternatives, such as the relatively inexpensive swap to the 1227748 PCM loaded with modified $58 code (4.3 90V6 Sycone /Typhoon, 2-bar, HEI Distributor, speed density) will typically offer "very" acceptable results.

[El-Stupido]

maybe i just dont understand how to read flow maps right. never done turbo before, i very well may be wrong, but it still seems to me that the higher rpms would suffer a drop in boost if i had it turned up to 8 psi, like after 4000rpm. this particular turbo came from a merkur xr4ti, a 2.3l 8 valve engine. if it was capable of 12-15psi on a 2.3, im sure the .5l makes a difference.

[Dave]

... I know those 2.3's very well, as I've been an avid freek of the SVO, Turbocoupe, Merkur XR4Ti, Mercuri Capri Turbo and the Mustang Turbo (from the fuel injected family, not carburated family)

in the newer years they used the IHI turbocharger, which is crap. it spools faster, but even on the 2.3's it proved not to be reliable. they can create 18 - 20lbs of boost on a good turbo exhaust manifold, however you see the turbin (exhaust) housing start to glow a nice orange/red - now on the earlier years the 84 - 86 turbocoupes, mustang turbos, capri turbos, and SVO's you see a Garrett T3, now if you can find a good T3/T4 Hybird, then you'd start to see some better results into the larger displacement engines. you also want to find the water & oil cooled units, as they will just last longer.

as for my rights to know this, I just hosted a Turboford Dyno Day in MN at John Haley Motorsports - good fun, we had a few 2.3 turbo's makin' over 200HP on the dyno (mine included) - I just sold my 1984 Mustang SVO - and now I've got a draw-thru carb-to-turbo setup in my 1980 Mustang, lots of good fun, easier to tune as there's no fuel management system.

now that's a 9:1 motor, and the only way I can get any good restults from higher boost (anything over 12psi) I have to run 110 octane leaded gasoline, I will be adding propane injection to help cool the charge and to add as a fuel modifier in the near future once I have that engine completed, figure I'd also note that I'm not intercooled, as that would be very bad since the carb is before the turbo like in the old GM Turbo Firebirds, Gand National's and such...

but that brings me to this little question - I am expirementing with my 88 Buick Regal, 2.8 with the MAF on it, wouldn't I be able to almost bypass the MAP sensor once it goes into boost (using a few 1-way check valves and such, same way whipple does it with the vortech V8 trucks) and allow it to read the MAF when under boost, making the MAP think that it's just at 0" of vacuum?

[Anonymous]

I am expirementing with my 88 Buick Regal, 2.8 with the MAF on it, wouldn't I be able to almost bypass the MAP sensor once it goes into boost (using a few 1-way check valves and such, same way whipple does it with the vortech V8 trucks) and allow it to read the MAF when under boost, making the MAP think that it's just at 0" of vacuum?

How about get rid of the MAF? Get a chip, airbox (or just use the IAT/MAT thats on the old MAF, but you still have the whole restrictive MAF unit in the way) and transmission speed sensor from a 1989 2.8.

[akira]

If your looking for a fuel octane alterative here is a weird one. The thinner Tolulene when mixed 10% total volume with gasoline or 9 parts fuel 1 part thinner will result in a octane rating of around 118. That is refrenced from an import racing mag. Try not to breathe the stuff in because after a while it will make your lungs numb and you will feel ill. But talk about flammible!!!

[3100rettaracer]

Mechanic, you turboed your 3100??? can you help me out??? like how did you do your crossover pipe and how much bosst you runing. also what parts did you all need??????

[evilmiata]

If your looking for a fuel octane alterative here is a weird one. The thinner Tolulene when mixed 10% total volume with gasoline or 9 parts fuel 1 part thinner will result in a octane rating of around 118. That is refrenced from an import racing mag. Try not to breathe the stuff in because after a while it will make your lungs numb and you will feel ill. But talk about flammible!!!

Mind sharing the name of that mag? Toluene has a RON octane rating of 121 and a MON rating of 107, leading to a (R+M)/2 rating of 114. (R+M)/2 is how ordinary fuels are rated in the US. So 9 parts 93 octane and 1 part tolulene (93 * 9) + (114 * 1) / 10 = 95.1. The most I've ever heard anyone use was a 2 to 1 ratio. I've seen guys mix up their own at autocross events, but can't remember what combinations they ran.

[Mechanic]

Mechanic, you turboed your 3100??? can you help me out??? like how did you do your crossover pipe and how much bosst you runing. also what parts did you all need??????

I answered this, or at least attempted to, in a reply to the PM you sent...

Xylene is another hydrocarbon that works well as an octane booster, so does tert-butyl alcohol, but its a bit hard to work with.

[akira]

The magazine is Modified Mag and it is issue 9/03 page 118 called Propane, Toluene, and Xylene. The article say "Besides most formulations (of race gas) are just increased levels of Toluene and Xylene. If you were to add 10 percent Toluene by volume to your gas tank you can expect an octane rating around 118 (using premium fuel)" I do know that Xylene evaporates much faster than Toluene but do not know the true numbers. I know of old time racers that used to use a good quanity of Moth Balls (99% Naptholene, used to make fireworks and explosives) and put them in with the best gas they could find, and they swear by it. That article is about altenatives for boost and N20 like propane injection.

[Anonymous]

I'd like to know more about propane injection.. would it work well on a stock 2.8 for a little extra boost? I saw on TV they set up prop.inj. on a diesel truck and it looked very easy to do (easier than NOS).

[nocutt]

I'd like to know more about propane injection.. would it work well on a stock 2.8 for a little extra boost? I saw on TV they set up prop.inj. on a diesel truck and it looked very easy to do (easier than NOS).

Better with high compression ratios...especially dynamically! Eg diesel + turbos or high boost turbo apps...